SpaceX

1886 readers

11 users here now

A community for discussing SpaceX.

Related space communities:

Memes:

!spaceflightmemes@sh.itjust.works

founded 1 year ago

MODERATORS

threelonmusketeers@sh.itjust.works

few@sh.itjust.works

What is the new stubby vacuum engine bell made of? (sh.itjust.works)

submitted 1 year ago by robbak@sh.itjust.works to c/spacex@sh.itjust.works

5 comments fedilink hide all child comments

WE know the original full-size bell is made from a very expensive niobium alloy, for heat resistance. But I notice that the new bell hardly glows at all - just very faintly at the extreme outer edge. The film cooling provided by the turbopump exhaust protects it completely.

So, I am wondering - are they still using that expensive niobium for the stubby nozzle? From what I can see of the bell, they could use simple mild steel and be perfectly OK.

you are viewing a single comment's thread
view the rest of the comments

[–] robbak@sh.itjust.works 1 points 1 year ago

The regular raptor bells (and the regular Merlin bells, which we are discussing here) are made from a copper-rich alloy, for high thermal conductivity. They are fully regeneratively cooled by the engine's fuel (kero or methane). The extensions are radiatively cooled, with the base section film cooled by bleeding the cooler turbopump exhaust in a ring around the base of the extension/lip or the nozzle.